As bone marrow cell growth enhancers, there are known erythropoietin (Miyake, T. et al., J.B.C., 252, 5558, 1977) and G-CSF (Nicola, N. A., Annu. Rev. Biochem., 339, 27-30, 1989). However, these enhancers are protein preparations and thus unsuitable for frequent administrations. Therefore, it has been desired to find a low molecular weight compound having an activity comparable to these substances.